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A unified approach to global program optimization
 In Conference Record of the ACM Symposium on Principles of Programming Languages
, 1973
"... A technique is presented for global analysie of program structure in order to perform compile time optimization of object code generated for expressions. The global expression optimization presented includes constant propagation, common subexpression elimination, elimination of redundant register lo ..."
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Cited by 308 (0 self)
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A technique is presented for global analysie of program structure in order to perform compile time optimization of object code generated for expressions. The global expression optimization presented includes constant propagation, common subexpression elimination, elimination of redundant register load operations, and live expression analysis. A general purpose program flow analysis algorithm is developed which depends upon the existence of an “optimizing function. ” The algorithm is defined formally using a directed graph model of program flow structure, and is shown to be correct, Several optimizing functions are defined which, when used in conjunction with the flow analysis algorithm, provide the various forms of code optimization. The flow analysis algorithm is sufficiently general that additional functions can easily be defined for other forms of globa ~ cod: optimization. 1. INTRODUCTION of the graph represent program control flow DossiA number of techniques have evolved for the bilities between the nodes at execution–time. compiletime analysis of program structure in order to locate redundant computations, perform constant
Elimination algorithms for data flow analysis
 ACM Computing Surveys
, 1986
"... A unified model of a family of data flow algorithms, called elimination methods, is presented. The algorithms, which gather information about the definition and use of data in a program or a set of programs, are characterized by the manner in which they solve the systems of equations that describe d ..."
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Cited by 53 (8 self)
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A unified model of a family of data flow algorithms, called elimination methods, is presented. The algorithms, which gather information about the definition and use of data in a program or a set of programs, are characterized by the manner in which they solve the systems of equations that describe data flow problems of interest. The unified model
Static caching for incremental computation
 ACM Trans. Program. Lang. Syst
, 1998
"... A systematic approach is given for deriving incremental programs that exploit caching. The cacheandprune method presented in the article consists of three stages: (I) the original program is extended to cache the results of all its intermediate subcomputations as well as the nal result, (II) the e ..."
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Cited by 47 (19 self)
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A systematic approach is given for deriving incremental programs that exploit caching. The cacheandprune method presented in the article consists of three stages: (I) the original program is extended to cache the results of all its intermediate subcomputations as well as the nal result, (II) the extended program is incrementalized so that computation on a new input can use all intermediate results on an old input, and (III) unused results cached by the extended program and maintained by the incremental program are pruned away, l e a ving a pruned extended program that caches only useful intermediate results and a pruned incremental program that uses and maintains only the useful results. All three stages utilize static analyses and semanticspreserving transformations. Stages I and III are simple, clean, and fully automatable. The overall method has a kind of optimality with respect to the techniques used in Stage II. The method can be applied straightforwardly to provide a systematic approach to program improvement via caching.
Data flow analysis in software reliability
 ACM Computing Surveys
, 1976
"... The ways that the methods of data flow analysis can be applied to improve software reliability are described. There is also a review of the basic terminology from graph theory and from data flow analysis in global program optimization. The notation of regular expressions is used to describe actions ..."
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Cited by 44 (0 self)
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The ways that the methods of data flow analysis can be applied to improve software reliability are described. There is also a review of the basic terminology from graph theory and from data flow analysis in global program optimization. The notation of regular expressions is used to describe actions on data for sets of paths.
Operator Strength Reduction
, 1995
"... This paper presents a new al gS ithm for operator strengM reduction, called OSR. OSR improves upon an earlier alg orithm due to Allen, Cocke, and Kennedy [Allen et al. 1981]. OSR operates on the static sing e assig4 ent (SSA) form of a procedure [Cytron et al. 1991]. By taking advantag of the pr ..."
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Cited by 29 (9 self)
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This paper presents a new al gS ithm for operator strengM reduction, called OSR. OSR improves upon an earlier alg orithm due to Allen, Cocke, and Kennedy [Allen et al. 1981]. OSR operates on the static sing e assig4 ent (SSA) form of a procedure [Cytron et al. 1991]. By taking advantag of the properties of SSA form, we have derived an alg ithm that is simple to understand, quick to implement, and, in practice, fast to run. Its asymptotic complexity is, in the worst case, the same as the Allen, Cocke, and Kennedy al gS ithm (ACK). OSR achieves optimization results that are equivalent to those obtained with the ACK alg orithm. OSR has been implemented in several research and production compilers
Experience with the SETL optimizer
 ACM Transactions on Programming Languages and Systems
, 1983
"... The structure of an existing optimizer for the very highlevel, set theoretically oriented programming language SETL is described, and its capabilities are illustrated. The use of novel techniques (supported by stateoftheart interprocedural program analysis methods) enables the optimizer to accom ..."
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Cited by 24 (0 self)
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The structure of an existing optimizer for the very highlevel, set theoretically oriented programming language SETL is described, and its capabilities are illustrated. The use of novel techniques (supported by stateoftheart interprocedural program analysis methods) enables the optimizer to accomplish various sophisticated optimizations, the most significant of which are the automatic selection of data representations and the systematic elimination of superfluous copying operations. These techniques allow quite sophisticated datastructure choices to be made automatically. Categories and Subject Descriptors: D.3.2 [Programmiug Languages]: Language Classificationsvery highlevel languages; SETL; D.3.4 [Programming Languages]: ProcessorscompUers; optimization; 1.2.2 [Artificial Intelligence]: Automatic Programmingautomatic analysis of algorithms; program modification; program transformation
Structuring Decompiled Graphs
 In Proceedings of the International Conference on Compiler Construction
, 1996
"... . A structuring algorithm for arbitrary control flow graphs is presented. Graphs are structured into functional, semantical and structural equivalent graphs, without code replication or introduction of new variables. The algorithm makes use of a set of generic highlevel language structures that inc ..."
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Cited by 21 (6 self)
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. A structuring algorithm for arbitrary control flow graphs is presented. Graphs are structured into functional, semantical and structural equivalent graphs, without code replication or introduction of new variables. The algorithm makes use of a set of generic highlevel language structures that includes different types of loops and conditionals. Gotos are used only when the graph cannot be structured with the structures in the generic set. This algorithm is adequate for the control flow analysis required when decompiling programs, given that a pure binary program does not contain information on the highlevel structures used by the initial highlevel language program (i.e. before compilation). The algorithm has been implemented as part of the dcc decompiler, an i80286 decompiler of DOS binary programs, and has proved successful in its aim of structuring decompiled graphs. 1 Introduction A decompiler is a software tool that reverses the compilation process by translating a pure binar...
Making Graphs Reducible with Controlled Node Splitting
 ACM Trans. Programming Languages and Systems
, 1997
"... To exploit instruction level parallelism in programs over multiple basic blocks, programs should have reducible control flow graphs. However, not all programs satisfy this property. A new method, called Controlled Node Splitting (CNS), for transforming irreducible control flow graphs to reducible co ..."
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Cited by 15 (0 self)
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To exploit instruction level parallelism in programs over multiple basic blocks, programs should have reducible control flow graphs. However, not all programs satisfy this property. A new method, called Controlled Node Splitting (CNS), for transforming irreducible control flow graphs to reducible control flow graphs is presented. CNS duplicates nodes of the control flow graph to obtain reducible control flow graphs. CNS results in a minimum number of splits and a minimum number of duplicates. Since the computation time to find the optimal split sequence is large, a heuristic has been developed. The results of this heuristic are close to the optimum. Straightforward application of node splitting resulted in an average code size increase of 235% per procedure of our benchmark programs. CNS with the heuristic limits this increase to only 3%. The impact on the total code size of the complete programs is for a straightforward application of node splitting 13.6%. When however CNS with the he...
Principled Strength Reduction
 Algorithmic Languages and Calculi
, 1996
"... This paper presents a principled approach for optimizing iterative (or recursive) programs. The approach formulates a loop body as a function f and a change operation \Phi, incrementalizes f with respect to \Phi, and adopts an incrementalized loop body to form a new loop that is more efficient. Thre ..."
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Cited by 10 (9 self)
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This paper presents a principled approach for optimizing iterative (or recursive) programs. The approach formulates a loop body as a function f and a change operation \Phi, incrementalizes f with respect to \Phi, and adopts an incrementalized loop body to form a new loop that is more efficient. Three general optimizations are performed as part of the adoption; they systematically handle initializations, termination conditions, and final return values on exits of loops. These optimizations are either omitted, or done in implicit, limited, or ad hoc ways in previous methods. The new approach generalizes classical loop optimization techniques, notably strength reduction, in optimizing compilers, and it unifies and systematizes various optimization strategies in transformational programming. Such principled strength reduction performs drastic program efficiency improvement via incrementalization and appreciably reduces code size via associated optimizations. We give examples where this app...
Incremental Computation: A SemanticsBased Systematic Transformational Approach
, 1996
"... ion of a function f adds an extra cache parameter to f . Simplification simplifies the definition of f given the added cache parameter. However, as to how the cache parameter should be used in the simplification to provide incrementality, KIDS provides only the observation that distributive laws can ..."
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Cited by 9 (3 self)
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ion of a function f adds an extra cache parameter to f . Simplification simplifies the definition of f given the added cache parameter. However, as to how the cache parameter should be used in the simplification to provide incrementality, KIDS provides only the observation that distributive laws can often be applied. The Munich CIP project [BMPP89,Par90] has a strategy for finite differencing that captures similar ideas. It first "defines by a suitable embedding a function f 0 ", and then "derives a recursive version of f 0 using generalized unfold/fold strategy", but it provides no special techniques for discovering incrementality. We believe that both works provide only general strategies with no precise procedure to follow and therefore are less automatable than ours. Chapter 4 Caching intermediate results The value of f 0 (x \Phi y) may often be computed faster by using not only the return value of f 0 (x), as discussed in Chapter 3, but also the values of some subcomputation...